JPS5828757B2 - Porcelain composition for electric circuit boards - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic composition for an electric circuit board, particularly a ceramic composition suitable for a multilayer circuit board.

Imada: As electronic equipment becomes smaller, ceramic multilayer circuit wiring technology is becoming more and more important, and alumina ceramic substrates are used as the ceramic substrates for this ceramic multilayer circuit.

This alumina porcelain substrate has a firing temperature of 1500°C to 16°C.
Since the temperature is in the range of 00°C, when silver or the like is used as an electrode material for circuit wiring, the silver or the like turns into a metal oxide at the same temperature during firing, and the firing cost is high.

Palladium, gold, or platinum will not react or oxidize with the substrate, but since they are precious metals, they are very expensive.

In order to eliminate the above-mentioned drawbacks of alumina substrates, the present invention provides suitable characteristics as a circuit board, namely, a coefficient of linear expansion (α) of 7×10′/°C or less, and a bending strength of 10
00 kg/crA or more, quality factor Q (Q = 1 /
The purpose is to provide a ceramic composition for circuit boards that has a property of tan δ (where tan δ is dielectric loss tangent) of 500 or more and has a sintering temperature of 1300°C or less. ~3.26 wt%, SrO 0.50~45.33 wt% MgO 1.38~26.
07N amount%, AlO 10.92-59.50% by weight
, containing SiO2 in a proportion of 31.68 to 57.61% by weight.

The present invention will be explained in detail below.

First, let me explain the process of making sample number 1 in the attached table.
Al2O3 powder 31.42% by weight and SiO2 powder 35% by weight
．． 46% by weight, 1.88% by weight of Li2O powder, and Mg
12.93 wt% O powder and 18.31 wt% SrO
SrCO3 powder (1.42 times the weight of SrO) (the purity of these powders is 99.5%) was prepared.

These powders were placed in a polyethylene pot and wet mixed by ball milling with alumina balls for about 15 hours.

Next, this mixture was dehydrated and dried, then pre-calcined at about 850° C. for about 2 hours, and then placed in a polyethylene pot and pulverized by ball milling with alumina balls.

Next, about 20% by weight of polyvinyl alcohol was added to the total weight of the mixed powder and granulated to produce aggregates.

Next, in order to obtain a sample for measuring electrical properties, the aggregates were uniformly filled into a mold, pressure-molded at about 1000 kg/crA, and fired in the atmosphere at 1220°C for about 3 hours.
Diameter 16m1rL1 wall thickness 11n71L, composition Li20
1.88% by weight, 5r018.31% by weight, Mg012
．． 93% by weight, A120331.42% by weight, 5in2
A 35.46% by weight disc sample was prepared.

Silver paste was then printed in concentric circles on both main surfaces of the disc using 200 mesh screen printing, and 76 meshes were printed in the atmosphere.
After baking at 0℃ for 20 minutes, it has a diameter of 14mm and a thickness of 5.
The sample was completed by forming micrometer electrodes.

The relative permittivity εS in the attached table has the same composition, dimensions, and firing conditions as determined under the measurement frequency of IMHz.

It is the average value of 10 samples, and the quality factor Q (Q=
1/lan δ) is also the average value of the 10 samples obtained under the frequency of KIMHz.

The insulation resistance was measured for the 10 samples 30 seconds after applying a voltage of 100 cm at 25° C. and 50% humidity, and the lowest value was taken as the measured value.

Next, in order to measure the physical properties, the aggregates were uniformly filled into a mold, pressure-molded with a force of 1000 kg/crA, and baked at 1220°C for 3 hours to form a mold with a length of 20 mm.
Using a rectangular plate sample with a width (W) of 10 wm and a thickness (t) of 2 mm, the coefficient of thermal expansion (α) is 20°C to 50°C.
The bending strength (τ) was measured at a temperature change of 0°C, and the maximum breaking load Pm (kg) was measured at a distance between supports (1) of 7 mm.
(kg/ci).

The manufacturing process and measurement conditions for Sample 1 have been described above, but samples Nos. 2 to 30 also have Li2O powder, 5rC03 powder, MgO powder,
Al2O3 powder and SiO2 powder were prepared respectively.

That is, the SrCO3 powder is SrO
It was weighed at about 142 times the weight so that the weight % was obtained.

Other powders were weighed and prepared in the same weight percent as the composition shown in the attached table.

Note that the manufacturing process and measurement conditions for each sample are exactly the same, so their trial mounting will be omitted.

As shown in the above implementation σi], L120 0.12
・~3.26% by weight, Sl Qo, 50-45.33% by weight, MgO1, 38-26.07% by weight, Al 2C
, 310, 92~s9.5o, i amount%, Sin, 21
]-668 to 57.61 weight by weight, the sintering temperature could be lowered to 1300° C. or lower due to the synergistic effect of each component.

This allows the electrodes in the ceramic multilayer circuit to be silver-palladium electrodes.

In particular, in Samples 4.7.12.14 and 19, silver electrodes can be used, and the manufacturing cost of the ceramic multilayer circuit can be reduced to 11].

In addition, quality coefficients Q of 500 to 2500 are obtained,
It can be used in the UHF band without any practical problems.

Especially in the samples with sample numbers 5.9.11 and 16,
Since it is 2300 to 2500, it can be used in a wide range.

Furthermore, the thermal expansion coefficient α (20°C to 500°C
) is 2. Since it is in the range of OX5.5X106/℃,
In order to efficiently dissipate heat from an LSI chip, an attempt can be made to bond the heat dissipating surface of the metal layer of the LSI chip onto the electrodes of the circuit board by metal fusion at a temperature of about 300°C.

That is, the thermal expansion coefficient of silicon wafer, which is the base material of LSI chips, is 2.5 to 35 x 10-6/℃ (20 to 5'OO
℃), LS during cooling after metal fusion bonding
This has the effect that the I-chip can be attached without being destroyed.

In particular, in the samples of sample numbers 1, 5, 9, 15, and 18, the sintering temperature is in the range of 1100 ° C to 1220 ° C,
The quality factor Q is also very high, and the thermal expansion coefficient is 3.2 to 4.
It is in the range of 8x10-6/°C, and is a very useful ceramic composition when directly attaching LSI chips.

When a substrate that is resistant to thermal shock is required, the thermal shock strength is the bending strength τ(k
g/ci) and inversely proportional to the coefficient of thermal expansion, samples with sample numbers 1, 5, 7, 8, 10, 12, 15 and 19 have excellent thermal shock strength. Nos. 10 and 12 are superior to the alumina substrate, and other than that, are almost equivalent to the alumina substrate.

Samples Nos. 1 and 5 are very excellent in each of the above-mentioned properties, and can be used in a wide range of applications including alumina substrates and mullite substrates.

Although each of the above-mentioned characteristics in the composition of the above-mentioned example was obtained from the synergistic effect of each component, we will purposely describe the effect of a solid solution consisting of three or two of the five components and the effect of each component. and becomes as follows.

That is, Li20-Al2O3・n5i02 (n=1, n
-2 (eucryptite), n-4 (beta sposimene)] (hereinafter referred to as L), MgO-A1203 (spinel, hereinafter referred to as S) 2Mg0・2A1203・55in2 (cordierite,
(hereinafter referred to as C), 5rSi03 (strontium,
Regarding silicates (hereinafter abbreviated as Sr), increasing the amount of S, lowers the sintering temperature, increasing the amount of S, C, increases the sintering temperature, increasing the amount of L and C lowers the quality factor Q, As Sr and S increase, the quality factor Q increases,
When L and C are increased, α becomes smaller, when L and Sr are increased, the bending strength becomes smaller, and when S and C are increased, the bending strength becomes larger.

Regarding each component, as Li2O is reduced,
The coefficient of thermal expansion tends to increase, and the sintering temperature also increases.

When Li2O is less than 0.12% by weight, the above tendency becomes noticeable as shown in sample number 21.

Conversely, when Li2O is increased, the bending strength (τ) becomes smaller and the quality factor Q also becomes smaller.

(Refer to sample number 22) When the amount of SrO decreases, the coefficient of thermal expansion becomes small, and the quality factor Q tends to decrease by 0.5.
If it is less than % by weight, the tendency is poor as shown in sample number 23, and the basic conditions of the substrate are not satisfied.

As the amount of SrO increases, the bending strength of sample number 2 increases.
850 kg/cri as known from the characteristics of sample 4.
It becomes small as t.

As the amount of MgO decreases, the sinterability becomes worse and the firing temperature decreases, and as shown in sample No. 25, the quality factor Q becomes ioo, which is the same as that of sample No. 22.

If the amount of MgO is too large, the coefficient of thermal expansion will be high <26.
If it exceeds 0.7% by weight, the sintering temperature will be as high as 1420°C, as in sample No. 26, and the object of the present invention will not be achieved.

When Al2O3 decreases, the bending strength τ decreases,
If it is less than 10.92% by weight as in sample number 27, it becomes 900, which poses a practical problem.

As the Al2O3 content exceeds 59.50% by weight, the sintering temperature becomes 1450° C. as shown in sample No. 28, and the object of the present invention is not achieved.

In addition, as SiO2 decreases, sinterability worsens,
The sintering temperature is also high, the coefficient of thermal expansion becomes large, and Q becomes small.

(Refer to sample No. 29) When Si02 exceeds 57.61% by weight, the bending strength decreases and the quality factor Q also decreases.

When the sample number is 59.48% by weight, as in sample number 30, the quality factor Q is as low as 400 and the bending strength is also as low as 900.

In the above examples, in order to make a porcelain composition, powders of Li2O, Al2O3, 5i02, and MgO were used, and SrCO3 powder was used for SrO, but Li2C03L was used instead of Li2O.
iF powder may be used, and instead of A12030, Al2(
OH)3 may also be used.

In addition, petalite (Li20・Al2O3・8SiO2
・nH2O), sposimene (Li20-A1203.4
SiO2・nH2O) and eucryptite (Li20-A1203・2SiO2・nH2O) are used, and Li2O is added to it so that it has a predetermined composition during firing.
, Al2O3, and 5i02 may be prepared.

Furthermore, instead of each single powder of MgO1A1203 and SiO2, cordierite (21VIg0・2A1203・
5Si02), and MgO,, Al2O3, S
A required amount of iO2 alone powder may be prepared.

In addition, mullite (3A1203・2SiO□), carrion (A1203・2SiO3・2H,20), talc (
3MgO-4Sin2-nH2O) can also be used in the same manner.

As described above, the ceramic composition for electric circuit boards of the present invention has Li
0.12 to 3.26% by weight of O2, 0.50 to 3.26% of SrO
45.33 wt%, MgO 1.38-26.07 wt%, Al2O3 1 (192-59.50 wt%, Si
It contains O□ at a ratio of 11.68 to 57.61% by weight, has a sintering temperature of 1300°C or less, a linear expansion coefficient of 7 x 10-6/'C or less, and a bending strength of Since it has the characteristics of 1000 kg/crA or less and a quality factor Q of 500 or more, it is suitable as an electric circuit board material, and inexpensive materials such as silver and silver-palladium can be used as circuit wiring materials. This has the effect of significantly reducing the manufacturing cost of electric circuit boards.

Claims (1)

[Claims] 1 0.12 to 3.26% by weight of Li2O, 0% of SrO
．． 50-45.33% by weight, 1.38-26% MgO.
A ceramic composition for an electric circuit board, characterized in that it contains A1□03 in a ratio of 0'7% by weight, A1□03 in a ratio of 10.92 to 59.50% by weight, and SiO2 in a ratio of 11.68 to 57.61% by weight.